Philosophical literature teems with these topics, but it may suffice here to call the attention of the general reader to two or three easily readable summaries—one an explanatory article by Mr. Gerald Balfour, in The Hibbert Journal for April 1910, on the Epiphenomenon controversy, and generally on the alternative explanations of the connexion between Mind and Body, in the light thrown on the subject by Telepathy and Psychical Research; while on the vitality controversy a small book embodying a short course of lectures by the physiologist and philosopher Dr. J. S. Haldane under the title Mechanism, Life, and Personality, or a larger book by Professor M'Dougal called Body and Mind, may be recommended. On this subject also the writings of Professor J. Arthur Thomson may be specially mentioned.
The opinions of the present author on these topics, whatever they may be worth, are held without apology or hesitation, because to him they appear the inevitable consequence of facts of nature as now known or knowable. Some of these facts are not generally accepted by scientific men; and if the facts themselves are not admitted, naturally any conclusion based upon them will appear ill-founded, and the further developed structure illusory. He anticipates that this will be said by critics.
In so far as the author's manner of statement is in terms of frank Dualism, he regards that as inevitable for scientific purposes. He does not suppose that any form of Dualism can be the last word about the Universe; but, for practical purposes, mind and matter, or soul and body, must be thought of separately, and it must be the work of higher Philosophy to detect ultimate unity—a unity which he feels certain cannot possibly be materialistic in any sense intelligible to those who are at present studying matter and energy.
It may be doubted whether Materialism as a philosophy exists any longer, in the sense of being sustained by serious philosophers; but a few physiological writers, of skill and industry, continue to advocate what they are pleased to call Scientific Materialism. Properly regarded this is a Policy, not a Philosophy, as I will explain; but they make the mistake of regarding it as a Philosophy comprehensive enough to give them the right of negation as well as of affirmation. They do this in the interest of what they feel instinctively to be the ultimate achievement, a Monism in which mind and matter can be recognised as aspects of some one fundamental Reality. We can sympathise with the aim, and still feel how far from accomplishment we are. Nothing is gained by undue haste, and by unfounded negation much may be lost. We must not deny any part of the Universe for the sake of a premature unification. Simplification by exclusion or denial is a poverty-stricken device.
The strength of such workers is that they base themselves on the experience and discoveries of the past, and, by artificial but convenient limitation of outlook, achieve practical results. But they are not satisfied with results actually achieved—they forget their limitations—and, by a gigantic system of extrapolation from what has been done, try to infer what is going to be done; their device being to anticipate and speak of what they hope for, as if it were already an accomplished fact. Some of the assumptions or blind guesses made by men of this school are well illustrated by an exposition in The Hibbert Journal for July 1916, where an able writer states the main propositions of Scientific Materialism thus:—
1. The law of universal causation;
2. The principle of mechanism—i.e. the denial of purpose in the universe and all notions of absolute finalism or teleology;
3. The denial that there exists any form of 'spiritual' or 'mental' entity that cannot be expressed in terms of matter and
motion.
These appear to be its three propositions, and they are formulated by the exponent "as being of the first importance in the representation of materialistic thought."
Now proposition 1 is common property; materialistic thought has no sort of exclusive right over it; and to claim propositions 2 and 3 as corollaries from it is farcical. Taking them as independent postulates—which they are—all that need be said about proposition 2 is that a broad denial always needs more knowledge than a specific assertion, and it is astonishing that any sane person can imagine himself to know enough about the Universe as a whole to be able complacently to deny the existence of any "purpose" in it. All he can really mean is that scientific explanations must be framed so as to exhibit the immediate means whereby results in nature are accomplished; for whether, or in what sense, they are first or simultaneously conceived in a Mind—as human undertakings are—is a matter beyond our scientific ken. Thus Darwinian and Mendelian attempts to explain how species arise, and how inheritance occurs, are entirely legitimate and scientific. For our experience is that every event has a proximate cause which we can investigate. Of ultimate causes we as scientific men are ignorant: they belong to a different region of inquiry. If the word "denial," therefore, in the above proposition is replaced by the phrase "exclusion from practical scientific attention," I for one have no quarrel with clause 2; for it then becomes a mere self-denying ordinance, a convenient limitation of scope. It represents Policy, not Philosophy.